JPS6027860B2 - hydraulic shock absorber silencer - Google Patents

Description

Detailed Description of the Invention For example, in a hydraulic shock absorber used in a door checker or a suspension system for a car body, an orifice for generating a damping force is provided in an inner cylinder in which a piston is slidably engaged, and an outer cylinder is provided on the outside of the inner cylinder. Some have a structure that is a combination of

In such a hydraulic shock absorber, when oil is ejected from the orifice at high speed due to rapid movement of the piston, the oil impacts the inner surface of the outer cylinder and generates abnormal noise. In particular, hydraulic shock absorbers for door checkers have the disadvantage of producing unpleasant noises when the door closes rapidly due to strong winds. The present invention seeks to eliminate these drawbacks. Fig. 1 is a vertical sectional view of the main part of the embodiment of the present invention, Fig. 2
The figure is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is an enlarged view of a part of FIG. 1.

In this way, the piston 2 is fitted into the inner cylinder 1 at will,
The outer cylinder 3 is coaxially attached to the inner joint. In addition, the piston 2 is fitted with an O-ring 4 and is provided with an oil passage having a check valve (not shown), and rod guides and oil seals are provided at the upper ends of the inner cylinder 1 and outer cylinder 3, so that the piston rod 5 has been combined with these. Furthermore, an oil passage is provided in the lower part of the inner cylinder 1 to carry the inside of the inner cylinder to the cylindrical gap between the inner cylinder and the outer cylinder, and the inside of the oil passage is filled with oil 6, and the inner cylinder 1 is filled with oil 6. A plurality of damping force generating orifices 7, 8, etc. arranged in the axial direction are provided. In such a hydraulic shock absorber, the present invention provides a shield on the outside of the inner cylinder 1 facing the orifices 7 and 8 to prevent oil ejected from the orifices from impacting the inner surface of the outer cylinder 3. 9
It has been established. That is, in the above embodiment,
A cylindrical shield 9 is provided on the outside of the inner cylinder 1 so as to face the orifices 7 and 8, and a gap d of 0.1 to 1 is provided between the shield and the outer surface of the inner cylinder 1. There is. FIG. 4 is a cross-sectional view of the same part as FIG. 2 in another embodiment, in which a shielding body 9 made of a rectangular plate of elastic material bent into a C-shape is tightly fitted into the inner cylinder 1. Therefore, normally the shield 9 is in close contact with the outer surface of the inner cylinder 1 due to its elasticity, but when the oil 6 is ejected from the orifice 7 or 8, the shield 9 is bent as shown by the chain line due to the pressure, and the inner cylinder A gap d of 0.1 to 1 side is formed between the shield member 9 and the shield member 9 . FIG. 5 is an enlarged view of a part of FIG. 4 in this state. As described above, the present invention includes orifices 7 and 8 formed in the inner cylinder 1 for generating damping force.
A shielding body 9 is provided on the outside of the housing.

That is, when the piston 2 moves downward in FIG.
Since the oil passage provided in this piston is opened, the oil in the lower part easily flows out to the upper part, and the oil corresponding to the volume of the piston rod inserted into the inner cylinder surface flows through the oil passage in the lower part of the inner cylinder into the inner cylinder. The damping force easily flows into the gap between the outer cylinder and the outer cylinder, generating a relatively small damping force. However, when the piston 2 moves upward in FIG. 1, the oil passage of the piston is closed, and the oil in the upper part of the piston is ejected into the gap between the inner cylinder and the outer cylinder through the orifices 7, 8, etc. A damping force is generated, and as the piston moves upward, the number of orifices through which oil is ejected decreases, so the damping force gradually increases. In this case, since the oil ejected from the orifice 7 or 8 has an extremely high velocity, if there is no shield 9, this oil will impact the inner surface of the outer cylinder 3 and cause vibrations in the outer cylinder, causing a large difference. A sound is generated. However, since the shield 9 is provided so as to face the orifices 7, 8, etc., the ejected oil hits the shield 9 and spreads in all directions as shown by the arrows in FIG. 3 or 5. , flows out parallel to the axis from an arc-shaped gap between the upper end or the lower end of the shield and the inner cylinder. This prevents the spouted oil from hitting the outer cylinder 3 and causing the outer cylinder to generate abnormal noise. Further, by making the gap d between the shield 9 and the inner cylinder 1 sufficiently small, a considerable portion of the damping force can be generated in the gap between the shield 9 and the inner cylinder 1. Therefore, the flow rate of the oil flowing through the orifice 7 or 8 can be reduced to prevent vibrations from occurring in the shield 9.
Moreover, since the shielding body 9 is submerged in oil, vibrations are easily attenuated, and by setting the gap d to 1 or less, it is possible to ensure that abnormal noise is generated due to the vibration of the shielding body. can be prevented. A desired damping force can be obtained by adjusting the distance 1, 12 from the orifice 7 or 8 to the green of the shield 9. In addition, as in the embodiments shown in FIGS. 4 and 5, the shield 9 is normally kept in close contact with the inner cylinder, and when oil is ejected from the orifice 7, etc., it is bent by its elasticity to form the gap d. , the shield acts as a check valve, and the damping force characteristic between the moving speed of the piston and the damping force is 2.
It is possible to change the characteristic from the power characteristic to the 2/Minatoniwa characteristic or any suitable characteristic in between. In this way, in the present invention, by arranging the shielding body opposite to the orifice formed in the inner cylinder through a gap of one side or less, the oil ejected from the orifice impacts the inner surface of the outer cylinder and generates abnormal noise. This is to prevent this.

In addition, since a considerable portion of the damping force is generated in the gap between the inner cylinder and the shield, the magnitude of the damping force can be accurately set to a desired value by adjusting the gap d, length 1, etc.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of the main part of the embodiment of the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, Fig. 3 is an enlarged view of a part of Fig. FIG. 5 is a sectional view of the same portion as FIG. 2 in another embodiment of the invention, and FIG. 5 is an enlarged view of a portion of FIG. 4 in an operating state. In the figure, 1 is the inner cylinder, 2 is the piston, 3 is the outer cylinder,
4 is an O-ring, 5 is a piston rod, 6 is oil, 7 and 8 are orifices, and 9 is a shield. 3 Nephew Shiozu Kasai/Gen Oza Enzuru

Claims (1)

[Claims] 1. In a hydraulic shock absorber, an outer cylinder is coaxially fitted into an inner cylinder into which a piston is slidably fitted, the inside of which is filled with oil, and an orifice for generating a damping force is formed in the inner cylinder. A shield is disposed on the outside of the cylinder to face the orifice to prevent oil ejected from the orifice from impacting the inner surface of the outer cylinder, and the gap between the shield and the inner cylinder is 1 mm or less. A silencer characterized by the following: